With the pounding, never-ending headache of trying to secure a Brexit deal, Theresa May could do with some cheering up.

She probably didn’t expect it to come from the Labour Party.

But on Monday that’s what she got. Seven Labour MPs resigned from the party in protest at Jeremy Corbyn’s approach to Brexit and allegations of anti-Semitism within its ranks.

The MPs who quit were Luciana Berger, Ann Coffey, Mike Gapes, Chris Leslie, Gavin Shuker, Angela Smith and Chuka Umunna. The following day they were joined by an eighth MP, Joan Ryan.

However, the celebrations in Conservative Central Office didn’t last long. On Wednesday three pro-Remain Tory MPs – Heidi Allen, Anna Soubry and Sarah Wollaston – all quit their party, saying it had moved too far to the right, and joined the new grouping.

More resignations from both parties are expected. And it is beginning to seem as if the division in politics is as much between pro-EU and anti-EU as it is between left and right.

All political parties are broad churches, with different factions and shades of opinion, but sometimes the divisions between them become too wide to straddle. And nothing is more divisive at the moment than Europe.

To many people this week’s news carries strong echoes of 1981, when four high-profile and long-serving Labour MPs - Roy Jenkins, David Owen, Bill Rodgers and Shirley Williams – left to form the Social Democratic Party.

The new party entered into a coalition with the Liberals, promising to “break the mould” of British politics.

But they never made the breakthrough they hoped for, and after the 1987 general election the SDP merged with the Liberals to become the Liberal Democrats. So the mould has remained largely intact – with two large parties and a third, smaller one.

Will events take a different turn this time? Any new party may face the same difficulties as the SDP under our first-past-the-post election system.

It would take a change to proportional representation (PR) to give them a better chance. Under PR, there is a direct relationship between the percentage of votes a party wins and the percentage of seats they receive. And Jill Perry believes this is now possible.

Mrs Perry is a Green Party candidate for Allerdale Council in May’s local elections and has also stood for the party in general and European elections. Yet despite the Greens’ level of support they only have one MP.

The Greens, the Lib Dems and the SNP all support PR. She says the new party will be an extra voice in favour of it. Add that to dissatisfaction with the two main parties, and change is possible.

“Both main parties have really messed up over Brexit,” Mrs Perry said: “There are strong factions within the main parties who have a greater chance of winning under the existing system and aren’t going to want to change that. But we’ve now got significant groups in each party who are in favour of PR. A lot of MPs have made statements supporting it. It’s the best opportunity we’ve had for it for a long time. So I’m cautiously optimistic.”

The new group of independent MPs all support a second EU referendum on the final Brexit deal. But for the eight former Labour MPs it is not their only area of disagreement with Jeremy Corbyn.

In September 2015 former Copeland MP Jamie Reed resigned as shadow health minister, citing as his reason the new leader’s opposition to nuclear energy. Mr Reed then resigned as an MP in January 2017.

And this week’s leavers have also made allegations of anti-Semitism. Labour’s last leader, Ed Miliband, may have been Jewish - but one of those who’ve quit, Luciana Berger, says she has been subject to sustained anti-Jewish abuse.

So were they justified in breaking away? Ruth Alcroft, Labour’s candidate for Carlisle at the next general election, says she personally has not seen any examples of bullying or anti-Semitism.

“As a nation, we have to accept that anti-Semitism happens,” she concedes. “And there may be occasions when anti-Semitism happens in the party, because we are a party of people. It’s really, really important that if people feel that there is anti-Semitism we absolutely need to be dealing with it because it’s not acceptable.”

But she adds: “This had been taken up by the media and played as a card. There are newspapers which are strongly anti-Labour and anti-Jeremy Corbyn.

“This issue has been taken up as a stick to beat him with. It’s been exploited.”

When it comes to council elections, voters may be more likely to support new political groups, particularly if they have a local focus. After all, it won’t be up to a district council to negotiate a Brexit deal.

And Cumbria is seeing the emergence of new groupings in advance of this year’s local elections.

Opponents of Eden Council’s draft plan for future development are forming a new party to try to stop it. They are calling themselves Keep Penrith and Eden Special, and aim to put up candidates in all the wards in Eden except those where the sitting councillors already oppose the plan. Adrian Hill, who is leading the campaign, said: “We have people queuing up who want to stand for us.”

In Allerdale, a newly-formed group could be fielding up to 12 candidates in the local elections. The West Cumbria Independents have described themselves as “not politically aligned” and focused on creating a “fairer system” across the borough. They are being led by Stephen Stoddart, county and district councillor for Moorclose, and former Allerdale councillor for Maryport George Kemp.

They oppose the executive model of government in the borough and want to see it replaced. The group has 10 confirmed members but Mr Kemp said he expects to have at least a dozen ahead of the election in May.

Kerryanne Wilde, from Shap, and Richard Pitchford, from Carlisle, are both former Ukip members who formed a new party called WISE Reunited. It has since merged with another new grouping called the Time Party and Mrs Wilde will be standing for them in her home village in the elections.

“I think the more of these new parties come up, the better it is for the country,” she says. “They will get support for people whose voices haven’t been heard.”

Whether any of these groups make an impact remains to be seen. But with politics in such a state of flux, anything could happen.